1. Field of the Invention
The present invention relates to an optical disk which is formed by adhering two surfaces for forming information to an adhesive layer. More particularly, the present invention relates to an optical disk having an individual recognizing function, which can be managed as a product easily and effectively and in which the falsification can be prevented.
2. Description of the Related Art
Distribution media such as an optical disk are widely used due to the large capacity and the low cost for forming pits. In particular, various applications are proposed with a CD (Compact Disk) and a DVD (Digital Video Disk) by using the large capacity thereof.
In accordance with the large capacity for storing data in the optical disk, a variety of copy managements are proposed so as to prevent an easy copy. However, hacking causes heavy damage to copy managements all over the world.
Under such a situation, data is recognized every disk and an illegal copy is prevented. Further, the management for each optical disk is regarded as important for improving the protection of contents, the higher copy management, and the security.
Referring to FIG. 1, an optical disk 110 is used as an optical disk having the above-mentioned individual recognizing function according to the related art. The optical disk 110 is formed by adhering to an adhesive layer 3, surfaces having aluminum film forming areas 112a and 112b made of thin aluminum films on two ring disk-shaped polycarbonate substrates 111a and 111b. Main information is recorded to the aluminum film forming areas 112a and 112b by using laser beams or the like. The main information is read by radiating reading beams which are condensed by a condenser lens 115.
As shown in FIG. 1, a management identifier area 117 of an optical disk lot is provided at a center-side peripheral of the aluminum film forming area 112b to which the main information is recorded, on an inner-circumference portion 118 of the ring disk-shaped polycarbonate substrate 111b. Management information such as title, order name, and lot number is recorded to the management identifier area 117 by printing. In the case of the above recording, linear information upon exposure is recorded to the corresponding area such as a number, a character, and a barcode upon exposing an optical disk stamper, as surface information which can visually be recognized in general. In the manufacturing after exposing the optical disk stamper, a CCD camera or the like identifies and manages the management information. Consequently, it is advantageous to prevent trouble such as the mixing of foreign materials by identifying the above management information.
Further, as disclosed in Japanese Unexamined Patent Application Publication No. 2000-163883, main information is recorded to an optical disk. Additional-information area data is also recorded to the optical disk. In the above-described optical disk, effectively, the copyright of contents is protected and illegal software operation is prevented.
Referring to FIG. 2, an optical disk disclosed in the above Publication will be described in followings. The optical disk 200 has a main-information area 212 and an additional-information area 213 in a substrate 211 thereof. The additional-information area 213 has an area for inhibiting the reading of the recorded data and a control area indicating whether information on the prohibition of reading is present or absent. A reading device of the optical disk 200 does not externally output the information on the prohibition of reading and, therefore, the information on the prohibition of reading is not downloaded when information except therefor is downloaded. As a consequence, the information on the prohibition of reading includes a cipher key for the main information, thereby preventing the normal reading of cipher data which is downloaded. If the information on the prohibition of reading might be read, a manufacturer can find an illegal source by including management information such as an order side in the information on the prohibition of reading.
The optical disk having the conventional individual recognizing function has a problem to erroneously operate the optical disk to which data to be downloaded excluding the main information is recorded.
The management information on each optical disk is not subjected to a specific countermeasure.
In the related art shown in FIG. 1, the optical disk records the management information such as the title, the order-side name, and the lot identification information. In the case that high-priced data contents are installed in a CD-ROM, a management number for each customer is additionally input to the above-described management information. However, actually, each optical disk is not subjected to detailed management. Therefore, an optical disk having another management information might erroneously be operated by inputting the management number of any customer.
In the related art shown in FIG. 2, although the illegal copy and the falsification of the recorded contents are prevented, the management measurement against the downloading of information to an erroneous area is not adopted.
To solve the above-described problems, it is an object of the present invention to provide an optical disk having an individual recognizing function for effectively managing each optical disk, which is suitable to product management for easily inhibiting the illegal use of manufactured and sold optical disks.
In the present invention, there is provided an optical disk having an individual recognizing function and a ring disk-shaped body, comprising a first substrate having a first principal surface, a second substrate having a second principal surface, an adhesive layer, principally. The adhesive layer is sandwiched between the first principal surface of the first substrate and the second principle surface of the second substrate and to which the first substrate and the second substrate are adhered. And a ring disk-shaped main-information area to which main information is recorded or is read by laser beams, provided on at least one of the first principal surface and the second principal surface. In the above-described optical disk having the individual recognizing function, at least one of the first principal surface and the second principal surface has an individual recognizing area. On the individual recognizing area, identification information for uniquely recognizing the optical disk is recorded before adhering the first substrate and the second substrate. The individual recognizing area is placed to at least one of an inner-circumference portion and an outer-circumference portion adjacent to the main-information area on the substrate. This position exists when the optical disk is perspectively viewed in the vertical direction of the first principal surface and the second principal surface. In the individual recognizing area, after adhering the first substrate and the second substrate to the adhesive layer, the identification information can be read but cannot be recorded and changed by using the laser beams used for recording or reading the main information to the main-information area.
That is, the optical disk in the present invention is formed by adhesion of at least two surfaces used for forming information to the adhesive layer. The optical disk has the individual recognizing area for read only. The individual recognizing area is placed to at least one of an inner-circumference portion and an outer-circumference portion adjacent to the main-information area on the substrate for recording the main information to one of the adhering surfaces. At the individual recognizing area, the identification information for uniquely recognizing the optical disk is recorded.
With the above-described structure, when the optical disk is loaded, the identification information for each optical disk can be uniquely read from the individual recognizing area on the optical disk by using, e.g., the reading beams. Therefore, the downloading destination can certainly be confirmed. It is possible to read the recorded main information by only the reading device having identification information which completely matches the above-described identification information for each optical disk.
That is, the security can be highly ensured by using the management and the identification of each optical disk. Not only by inputting a password but also by combining the identification of the optical disk and the password, a user is determined or authenticated. Simultaneously, the optical disk can safely be used while highly maintaining the confidentiality of data.
Preferably, the above-described identification information may be recorded and formed by printing a pattern having a predetermined difference in tint at the individual recognizing area. With the structure, the printed identification information can be read by the reading beams and, further, can visually be recognized by the difference in tint. Therefore, upon loading, the optical disk can be identified and can be checked in advance.
Preferably, the pattern having the predetermined difference in tint may be at least one of a character, a number, a barcode, and a drawing. Further, preferably, the printing may be any of screen printing, ink-jet printing, offset printing, and ink stamp.
Moreover, with the above-described structure, the identification information for each optical disk is recorded to the individual recognizing area on the substrate surface which is adhered to the adhesive layer by the printing so as to prevent the easy falsification of the optical disk. Thus, the optical disk must be broken to change the data of the optical disk on purpose. Therefore, the above-described structure becomes safe against the falsification.
Preferably, the above-described individual recognizing area may be adjacent to a management area which is provided at a circumference portion of the main-information area. Further, the individual recognizing area can function as a part of the management area.
When two surfaces for forming information are adhered to an adhesive layer, the optical disk may comprise an individual recognizing area for read only on one of the adhering surfaces and a film forming area on the other of the adhering surfaces. At the individual recognizing area, identification information for uniquely recognizing the optical disk is recorded to at least one of an inner-circumference portion and an outer-circumference portion adjacent to a main-information area for recording main information on the surfaces. The film forming area is used for covering the individual recognizing area. Preferably, the film forming area for covering the individual recognizing area may be formed as a part of the main-information area.
With the above-described structure, the film forming area is total reflection or half-transparent, and reaches the back of a reading-beam irradiated surface of the individual recognizing area. Therefore, it is possible to identify with a higher recognizing ratio and with high contrast, the recorded contents having the difference in tint. In particular, advantageously, information such as a printed mark is visually checked.
As mentioned above, advantages of the present invention are as follows.
According to a first advantage, the product management of the optical disk can easily be performed.
Because, in the processing for manufacturing the optical disk, the printing enables the area whose tint can visually be identified, including the character, the number, the barcode, the drawing, etc. to be formed at an area other than the main-information area. Further, the security can effectively be assured by recognizing and collating the formed area with the reading beams or combining the formed area and a specific password after the recognition and collation.
According to a second advantage, the optical disk cannot be falsified.
Because, in the processing for manufacturing the optical disk, the area capable of identifying each optical disk can be formed by the printing before adhesion of substrates. Thus, the data at the formed area of the completed optical disk cannot be falsified. If performing such a falsification that the adhesion of the substrates in the optical disk is peered and new data is recorded, the polycarbonate (PC) substrate is broken or mechanical characteristics are extremely deteriorated because the strength of adhesion is high. The reading of the optical disk becomes impossible. Actually, the optical disk becomes unavailable.